The device according to the invention is more specifically applicable to the loading of fixed-bed catalytic chemical, petroleum or petrochemical reactors with solid particles in the divided state, which may take the form of balls, pellets, cylinders, disks, rods, or bodies of any other shape, but which are generally of relatively small size. These solid particles are, more specifically, chemically inert balls used in chemical reactors, molecular sieves, or catalyst pellets used in transformation reactions of chemical or hydrocarbon products, for example reforming, cracking, hydrocarbon desulfurization, or, more generally, the hydrotreatment of petroleum fractions. Such particles usually take the form of balls, extrusions or multilobe elements whose dimensions vary according to circumstances, from a few tenths of a millimeter to a few centimeters.
When these solid particles are loaded into a reactor, it is essential that they are deposited intact on the bottom of the reactor or on the bed support plate, because if they break into small fragments they may block the outlet manifold of the reactor or the support plate, creating a pressure difference between the reactor inlet and outlet, which has a highly adverse effect on the efficiency of the reaction in the reactor and ultimately on the quality of the operator's intended production process.
The solid particles (inert balls or catalyst particles) must therefore be loaded without breakage or wear, in other words without any impact between the particles or against the walls of the reactor, that is to say without the presence of energy which might result, for example, from an excessive fall velocity inside the reactor.
In his patent application FR-A1-2 829 107, the present applicant has proposed a serpentine or helical semi-rigid sleeve in which the particles descend by rolling along the inner face of the sleeve, the velocity of descent (and consequently the kinetic energy at the end of travel) being adjustable by varying the inclination of the slope of the sleeve. However, this device is bulky because of its serpentine or helical shape and the relative rigidity of the material from which the sleeve is made, making it difficult to transport, to install, and to dismantle through the passage openings (“manholes”) in the reactor.
In his patent application FR 2 874 212, the present applicant has also proposed a cylindrical flexible straight sleeve inside which a helical ramp, fixed on a central axis and wound around this axis, is used to limit the velocity of descent of the balls on said ramp. However, for very tall reactors, for example those with heights of more than thirty meters, there are potential hazards which may arise, for example, as a result of the tearing of the sleeve when it is fully loaded, in other words when its whole length is filled with solid particles. These hazards may potentially endanger the operators working at the bottom of the reactor.
In his application FR-A1-2 901 778, the present applicant has proposed a rigid sleeve formed from a plurality of basic units fastened to each other by sets of threaded rods and nuts positioned on the outside of the basic units. Each basic unit is provided with two diametrically opposed fastening flanges, each designed for attaching and/or guiding at least one fastening chain or line necessary for maintaining the sleeve inside the enclosure. This rigid sleeve includes at least one conduit for introducing particles into the reactor, in which a movable element for controlling the fall velocity of these particles is moved by means of a line. This movable element is conical or cylindrical in shape, with a height in the range from one to five times the inside diameter of the conduit, and is provided with a seal on its periphery to prevent the passage of particles between its periphery and the inner wall of the conduit.
However, this sleeve has the drawback of being particularly heavy and bulky because of the rigid material used to form each basic unit, and is therefore difficult to transport for use in reactors remote from each other or at industrial sites at a distance from its management and maintenance center. Furthermore, it is sometimes difficult to align the individual basic units correctly during their assembly, and this may lead to misalignment of the inner conduit portions of two adjacent basic units, causing the movable element to become jammed as it passes through the conduit.
Unlike the semi-rigid or flexible sleeve described in FR-A1-2 829 107 and FR-A1-2 874 212, the rigid sleeve described in FR-A1-2 901 778 cannot be flattened, curved or deformed.